With respect to an image display device (for example, a liquid crystal display, an organic EL display or a plasma display) attached to various equipment (for example, a television, a personal computer, a smart phone, a mobile phone or a vehicle), if outside light such as indoor lighting (such as fluorescent light) or sunlight is reflected in a display surface, visibility will decrease due to the reflected image.
As a method to suppress reflection of outside light, a method of disposing an antiglare film having irregularities on its surface, on the display surface of an image display device to diffusely reflect the outside light thereby to blur the reflected image may be mentioned.
As a method of forming an antiglare film, a method of applying a coating liquid containing a silica precursor such as a hydrolytic condensate of an alkoxysilane to a substrate by a spay method, followed by baking has been known (for example, Patent Document 1). In the case of forming an antiglare film by a spray method, a two-fluid spray nozzle is used in many cases.
By disposing an antiglare film to the display surface of an image display device, it is possible to suppress a decrease in the image visibility by reflection of the outside light in the display surface. However, at the same time, sparkle may occur on the surface of the antiglare film, whereby the image visibility decreases. Such sparkle tends to be significant as the antiglare property is higher. For example, in a case where an antiglare film is formed by a spray method, if the coating liquid is applied several times, the haze tends to be high and the antiglare property is increased, however, sparkle tends to be significant.
Patent Document 2 discloses to dispose a plurality of convex portions separately on a substrate e.g. for the purpose of suppressing sparkle of the image. Said convex portions are in the shape having at least one edge in a tableland shape or a substantially circular basin shape, having a size of a portion in contact with the substrate being from 50 to 250 μm. However, in Patent Document 2, the haze is at most 10%, and the antiglare property is insufficient.